Bidirectional polarized electromagnetic counter



Aug. 23, 1966 N. WALES, JR

BIDIREC'IIONAL POLARIZED ELECTROMAGNETIC COUNTER Filed Aug. 19, 1965 i ADD warmer a [arrow/m me- (SUB TPAC r) INVENTOR United States Patent 3,268,714 BIDIRECTIONAL POLARIZED ELECTRO- MAGNETIC COUNTER Nathaniel B. Wales, Jr., New York, N.Y., assiguor to The Metrodynamics Corporation, Red Bank, N.J., a corporation of New Jersey Filed Aug. 19, 1965, Ser. No. 480,977 2 Claims. (Cl. 235-92) This invention relates to an electromechanical counter for registering and displaying the total of electrical impulses impressed thereon in either an additive or subtraction mode, depending on the electrical polarity of such impressed signal impulses.

Heretofore, add-subtract counters have in general required the use of two separate drive magnets to achieve reversibility. The present invention greatly simplifies such reversible counters by teaching a novel principle in which use is made of the magnetic leakage field of a single drive electromagnet to select by means of a small permanent magnet responsive to this leakage field, which of two oppositely directed ratchet pawls will be enabled to drive the counter. This polarization principle thus makes possible an economic and compact design for reversible magnetic counters.

The principal object of this invention is to provide a means for utilizing the magnetic leakage field of a counter-driving electromagnet to select the direction of counting.

Another object of this invention is to provide a design for magnetic counters which will add for one polarity of applied electric impulse, and which will subtract for the opposite said polarity.

Still another object of the subject invention is to provide a reversible counter design in which the selection of counting direction and the storage of counter drive energy in a spring is accomplished during the energization of an electromagnet, while the driving of the counter is accomplished after the de-energization of said magnet by the energy stored in said spring, thereby simplifying the circuitry necessary [for propagating carry signals between different orders of interconnected counters.

Other objects and a clearer understanding of this invention may be had by reference to the'following detailed specification, taken in conjunction with the accompanying drawing which is a schematic view of the preferred form of the invention.

Referring to the drawing, numeral 1 designates a magnet coil contained in a bobbin 2 which surrounds a soft iron pole piece 3, which in turn, is secured to a soft iron return magnetic circuit member 4.

A soft iron armature 5 is provided, pivotally secured at one end to member 4, and engaging at its opposite end the fingers 6 of a drive lever 7.

Lever 7 is pivoted by a pin 8, secured to a counter frame 9, to which member 4 is also secured.

A spring 10 extends between a tab 11 secured to lever 7 and an anchor pin 12 also secured to frame 9.

Lever 7 is provided with two pivot pins 13 and 14 on which are freely journalled the subtracting pawl 15, and the adding pawl 16, respectively. Pawls 15 and 16 are linked together by a pawl link 17 in a parallelogram configuration so that they are constrained to angulate synchrononsly with one another. Pawl 16 is provided with a cylindrical permanent magnet secured thereto adjacent to and approximately parallel to the average position of armature 5.

The subject counter is provided with a utilization Wheel 19 which may be a display number wheel, or a print out wheel, or a switching rotor for readout and carry transfer, on a combination of any or all of these.

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Wheel 19 is journalled on a pin 20 secured to frame 9, and is provided with a bidirectional detent cam 21 against which a spring detent arm 22 secured to frame 9 bears, so as to urge wheel 19 to index to a predetermined plurality of angular registrations.

Wheel 19, which is preferably molded of a plastic material, is also integrally provided with two oppositely direction sets of ratchet teeth 23 and 24 lying in different planes, so as to co-operate with pawls 15 and 16, respectively, which may be seen to be on opposite sides of wheel 19. In the unenergized position shown, a stop tooth 26 integral with lever 7 engages one of the teeth of ratchet 23.

The operation of the foregoing device is as follows:

The energization of coil 1 by a direct current, having a polarity of potential labeled add in the drawing will cause a magnetic flux to link the members 1, 4 and 5 in such a. direction as to make the left side of armature 5 a North pole and the right side of armature 5 a South pole. Since the right end of permanent magnet 18 is a North pole and its left end is a South pole, this polarity of energization will cause a leakage field (designated 25) to escape from armature 5 so that the North pole of armature 5 will attract the South pole of permanent magnet 18. Since the left, or South pole, of magnet 18 is located at the largest lever arm from pivot 14, the foregoing magnetic attraction will dominate over the co-existing attraction of the opposite side of 5 and 18 and will produce a net clockwise torque on pawl 16 about pivot 14, thereby forcing pawl 16 into contact with ratchet teeth 24 While simultaneously forcing pawl 15 via link 17 out of contact with ratchet teeth 23.

The magnetic field linking members 3, 4 and 5 will then cause armature 5 to rotate counterclockwise about its heel on member 4 so as to close the gap between 3 and 5. Since armature 5 is coupled to lever 7 by fingers 6, the above motion of armature 5 will rotate lever 7 clockwise about pivot 8, while extending spring 10 and storing potential energy therein.

The foregoing motion of lever 7 will carry pawl 16 to engage the next tooth of ratchet 24 and remain engaged therewith as long as coil 1 is continued to be energized.

When coil 1 is then deenergized, spring 1%) will drive lever 7 counterclockwise about pivot 8 thereby causing pawl 16 to drive wheel 19 one step or count in the clockwise or additive direction about pivot 20. The tooth contour of both sets of ratchet teeth 23 and 24 is such that even though the selective torque on magnetic 18 disappears or the deenergization of coil 1, whichever pawl 16 or 15 is engaged, will be mechanically retained with the ratchet tooth it is driving throughout the stroke of spring 10, due to the overhang of the tooth contour.

Conversely, the energization of coil 1 by direct current having a polarity of potential label subtract in the drawing will generate a magnetic flux having the polarity indicated in parenthesis so that the left end of armature 5 is South and its right end is North. This polarity will cause the left South poles of members '5 and 18 to repel one another, thereby generating a net counterclockwise torque on pawl 16 about pivot 14. Due to link 17, this torque in turn will rotate pawl 15 counterclockwise about pivot 13, thereby engaging pawl 15 with ratchet 23 while disengaging pawl 16. Again armature 5 will drive lever 7 clockwise to cock spring 10 and pick up the next tooth on the subtracting ratchet 23. Detent 22 prevents any frictional torque on wheel 19 from displacing'it during the powered stroke due to the rubbing of pawl 15 or 16 on their respective ratchets.

On deenergization of coil 1, pawl 15 will then drive wheel 19 one step counterclockwise in the subtractive direction under the force of spring 10. Tooth 26 is designed to destroy the momentum of any spring driven displacement of wheel 19 at the end of a counting stroke.

It is evident that many changes will occur to those skilled in the art Within the scope of the present invention. This scope is defined in the following claims:

What is claimed is:

1. A bidirectional counter comprising: an electromagnet; a permanent magnet located'in the leakage field of said electromagnet when energized; a register member; means to drive said register member in incremental displacement by energy supplied by said electromagnet; and means responsive to the interaction of said permanent magnetic and said leakage field to select the direction of said register displacement.

2. A bidirectional counter comprising: a direct current electromagnet having a coil and an armature; a register wheel having two oppositely directed sets of ratchet teeth; means. to detent said register wheel in a plurality of predetermined positions; a forward drive pawl; a reverse drive pawl; mutually exclusive means to engage either said forward pawl or said reverse pawl in operative driving engagement with said corresponding set of ratchet teeth; means responsive to energy supplied by said electromagnet through the motion of said armature to drive said forward pawl or said reverse pawl into causing an incremental displacement of said register wheel; a permanent magnet; and means responsive to the interaction of said permanent magnet with the magnetic field of said electromagnet for selecting which of said pawls will displace said register wheel.

No references cited.

DARYL W. COOK, Acting Primary Examiner.

J. F. MILLER, Assistant Examiner. 

1. A BIDIRECTIONAL COUNTER COMPRISING: AN ELECTROMAGNET; A PERMANENT MAGNET LOCATED IN THE LEAKAGE FIELD OF SAID ELECTROMAGNET WHEN ENERGIZED; A REGISTER MEMBER; MEANS TO DRIVE SAID REGISTER MEMBER IN INCREMENTAL DISPLACEMENT BY ENERGY SUPPLIED BY SAID ELECTROMAGNET; AND MEANS RESPONSIVE TO THE INTERACTION OF SAID PERMANENT MAGNETIC AND SAID LEAKAGE FIELD TO SELECT THE DIRECTION OF SAID REGISTER DISPLACEMENT. 